This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Brain stroke ranks the third leading cause of death and disability in most developed countries, and is the second most common cause of death worldwide. Despite tremendous effort in thrombolysis and neuroprotection, no effective treatment is available for cerebral stroke in clinical settings. This is largely due to the inability of current treatments to repopulate the stroke lesion cavity with functional neurons and glia cells as substrates for structural repair. In support of this notion, neural transplantation strategies have been attempted to reconstruct the stroke cavity. Despite its efficacy in providing sustained functional recovery in the injured CNS, neural transplantation for cerebral stroke repair has had limited success, due to poor donor cell survival and functionality at the infarct site. In addition, ongoing hypoxia that is undergone by the ischemic tissue at the stroke lesion elevates tissue injury and inflammation. Our long-term goal is to rebuild the complete blood vessel network, followed by repopulation of the focal cerebral stroke lesion cavity with functional neural cells derived from human induced pluripotent stem cells (h-iPS) for sustained structural repair and functional recovery after cerebral stroke. The overall hypothesis is that a combined strategy based upon 1) complete reconstruction of blood vessel network at the stroke lesion zone, 2) repopulation of stroke zone with functional neural cells derived from h-iPS, and 3) suppressing scar formation surrounding the stroke lesion zone, would promote neural repopulation and host-integration at the stroke lesion zone, leading to significant improvement in neurological outcome in the cerebral stroke patients. Our preliminary data have demonstrated the efficacy of a functionalized injectable hydrogel in promoting the formation of a complete well-structured vasculature network that fills the stroke lesion zone. Using this in-situ crosslinkable hydrogel, a complete vasculature network that fills the stroke lesion cavity will be created after hydrogel injection into the lesion. Three specific aims will be pursued: + To optimize the composition and mechanical property of our in-situ crosslinkable hydrogel for the survival and axonal sprouting of h-iPS derived neurons in vitro. + To transplant h-iPS derived neurons with the optimized injectable hydrogel obtained from Aim 1 into the stroke lesion zone in vivo. + To prevent scar formation at the stroke lesion-host tissue interface through local controlled delivery of agents that block the biosynthesis of inhibitory ECM components using the injectable hydrogels. Our research develops injectable biomaterial-based tissue engineering paradigm to promote neural cell regeneration/integration, and improved neurorehabilitation after cerebral stroke. Using a comprehensive approach at the interface of stem cell biology, biomaterials, and tissue engineering, the proposed strategy holds remarkable promise to ultimately repair stroke lesion with functional neural cells for sustained functional recovery.